1. Field of the Invention
The present invention relates to Identification Friend or Foe (IFF) systems, but more specifically, it relates to novel types of bracket decoders for use with IFF systems.
2. Description of the Prior Art
Identification Friend or Foe (IFF) has long been a vital factor in tactical operations. IFF has progressed from the recognition of coats of arms and flags to the present day electronic systems. Todays IFF systems comprise interrogator subsystems and transponder subsystems. The interrogator subsystem asks the question of all unknown entities, "Who are you?". A transponder subsystem answers this question. Most present day Navy ships use one interrogator subsystem for each radar system. Some present day Navy ships use up to five or more interrogator subsystems.
Information sent from the interrogator subsystems is fed to various types of processsors and decoders, whose purposes, inter alia, are (1) to establish and declare targets, based on incoming video replies, and (2) to determine the correct range, and sometimes code, of the target in question for the mode interrogated.
At the present time, if more than one reply is present in some 40.60 or 60.90 .mu.sec window size, the processor may not recognize any targets. Some processors may recognize only the first and last targets, with all other targets being dropped regardless of window size if the reply spacing is inappropriate.
Consequently, there is a need in the prior art to be able to handle mutiple target situations so as to accurately pick out the proper number of targets when multiple replies are located at certain inappropriate spacings for existing systems.
The prior art as indicated hereinabove include some important advances in IFF systems. However, insofar as can be determined, no prior art IFF system incorporates all of the features and advantages of the present invention.